The present invention relates generally to balun components or structural subassemblies utilized in conjunction with antenna radome assemblies, and more particularly to a new and improved balun component or structural subassembly which comprises a two-sided printed circuit board substrate having a longitudinal axis, and wherein each side of the two-sided printed circuit board substrate is asymmetric with respect to itself but is in effect anti-symmetric with respect to the opposite side of the two-sided printed circuit board substrate in a 180xc2x0 out-of-phase manner such that the entire two-sided printed circuit board balun component or structural subassembly exhibits diametrical symmetry with respect to the longitudinal axis of the overall two-sided printed circuit board substrate.
Most direction finding systems utilize antenna sensor amplitude and phase comparison techniques in order to necessarily determine angle of arrival (AOA) information or data with respect to a distant emitter. Such antenna sensor amplitude and phase comparison assemblies or systems must exhibit well-behaved amplitude and phase patterns regardless or independent of polarization in order to reduce angle of arrival (AOA) errors. Some prior art balun components, devices, or structural subassemblies have in fact been developed for utilization within such antenna sensor amplitude and phase comparison assemblies or systems in an attempt to provide such well-behaved and unsquinted amplitude and phase patterns, however, their performance has unfortunately been limited to narrow frequency bandwidth parameters. Other prior art balun components or subassemblies comprise broadband devices, however, they require cumbersome coaxial implementation which renders the antenna sensor amplitude and phase comparison assembly or system unnecessarily and undesirably large. Still other prior art balun components or subassemblies are desirably small and light in weight but are not symmetrical and therefore do not provide the required well-behaved and unsquinted amplitude and phase patterns regardless or independent of polarization.
Still further, the balun components or subassemblies are often particularly adapted for cooperative use in conjunction with spiral circuit components or assemblies which are, in turn, operatively associated with radome elements or components of overall antenna radome assemblies. Such balun components or subassemblies conventionally comprise parallel strip transmission lines, however, such parallel strip transmission lines are known to have high impedance values on the order of 200 ohms due to their inherently low capacitance characteristics which renders impedance matching difficult to achieve. As a result, antenna efficiency and operating bandwidth are compromised within the printed circuit board line width and spacing tolerances.
A need therefore exists in the art for a new and improved balun component or structural subassembly which can be utilized within antenna sensor amplitude and phase comparison assemblies or systems wherein such balun component or structural subassemblies can provide well-behaved and unsquinted amplitude and phase patterns regardless or independent of polarization in order to reduce angle of arrival (AOA) errors, and wherein further, such balun components or structural subassemblies will exhibit broad frequency bandwidth parameters as well as good antenna radome assembly impedance matching characteristics.
Accordingly, it is an object of the present invention to provide a new and improved balun component or structural subassembly for use within antenna sensor amplitude and phase comparison assemblies or systems.
Another object of the present invention is to provide a new and improved balun component or structural subassembly for use within antenna sensor amplitude and phase comparison assemblies or systems which effectively overcome the various operational drawbacks or disadvantages characteristic of PRIOR ART antenna sensor amplitude and phase comparison assemblies or systems.
An additional object of the present invention is to provide a new and improved balun component or structural subassembly for use within antenna sensor amplitude and phase comparison assemblies or systems which can provide well-behaved and unsquinted amplitude and phase patterns regardless or independent of polarization in order to reduce angle of arrival (AOA) errors.
A further object of the present invention is to provide a new and improved balun component or structural subassembly for use within antenna sensor amplitude and phase comparison assemblies or systems which will exhibit broad frequency bandwidth parameters as well as good antenna radome assembly impedance matching characteristics.
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of a new and improved balun component or structural subassembly, for use within antenna sensor amplitude and phase comparison assemblies or systems, which comprises a two-sided printed circuit board substrate having a longitudinal axis, and wherein each side of the two-sided printed circuit board substrate is asymmetric with respect to itself but is in effect anti-symmetric with respect to the opposite side of the two-sided printed circuit board substrate in a 180xc2x0 out-of-phase manner such that the entire two-sided printed circuit board balun component or structural subassembly exhibits diametrical symmetry with respect to the longitudinal axis of the overall two-sided printed circuit board substrate.
As a result of the aforenoted asymmetric, anti-symmetric structural characteristics of the new and improved balun component or structural subassembly, the aforenoted diametrical symmetry with respect to the longitudinal axis of the overall two-sided printed circuit board substrate enables the operatively associated antenna sensor amplitude and phase comparison assemblies or systems to achieve well-behaved and unsquinted amplitude and phase patterns regardless or independent of polarization in order to reduce angle of arrival (AOA) errors. In addition, the anti-symmetric structure of the new and improved balun component or structural subassembly exhibits balanced output characteristics for operative cooperation with spiral circuit components or assemblies of radome elements or components of overall antenna radome assemblies. Still further, the new and improved balun component or structural subassembly lastly comprises tapered transformer structure which effectively converts the coaxial feed point impedance value to an impedance value at the output or downstream end which is able to achieve good impedance matching with the aforenoted spiral circuit component or assembly of the radome elements or components of the overall antenna structure. In addition, such tapered transformer structure positively affects or enhances the range of bandwidth frequencies over which the new and improved balun component or structural subassembly is capable of operating.